1. Field of the Invention
The disclosure relates generally to data access methods for memory devices, and, more particularly to data access methods capable of improving access performance of the memory devices.
2. Description of the Related Art
In general, memory devices, such as memory cards or USB flash drives with a flash memory, comprise a control unit and a flash memory in which the flash memory is used for storing data. The flash memory can be is used in an embedded system, a personal digital assist (PDA), a portable computer, a digital audio player, a digital camera and a mobile phone. The flash memory is one kind of non-volatile memory that can be erased electrically and can be re-programmed, and it is mainly implemented in memory cards or USB flash drives for storing data and transmitting data between computer systems and the digital products.
A flash memory may comprise multiple memory blocks and each memory block has multiple storing pages for storing data. Flash memories erase data in one memory block unit and program data in one storing page unit. Further, data can only be programmed to a storing page that does not contain data or an erased storing page. Thus, when data is to be programmed to a specific storing page of a memory block of the flash memory, data contained in the specific storing page must be erased first. And, when data within the flash memory has been erased, all storing pages of that memory block of the flash memory must also be erased at the same time.
However, each time a data erasing operation of the flash memory is completed, the control unit needs a waiting time period (e.g. 3 microseconds), to wait for the host to be ready. Thus, the next data erasing operation may only be performed after the waiting time period is completed, thereby reducing the performance of the memory device.